DEAR DOCTOR K: My father had a stroke and has become depressed during his long recovery. Will antidepressants help? I’m asking because of the damage the stroke has done to his brain.

DEAR READER: I remember a patient like your father. Before his stroke, he was outgoing, active in his church and community, and always cracking jokes. Then he was hit with a stroke that paralyzed his left arm and leg.

Fortunately, his speech and thinking were not affected, but his personality changed completely. He sat in bed saying very little to anyone who came in the room, including his family, friends and doctor. When physical therapists tried to get him to do exercises to build back the strength on his left side, he was mostly uncooperative. I was worried that the stroke had caused dementia, but it became clear he was as smart as ever.

He was depressed. About one in four people who’ve had a stroke develop major depression. You’re right that the injury to the brain from the stroke can itself cause changes in brain chemistry that lead to depression. However, depression also can be a reaction to the impairments caused by the stroke. In other words, depression following a stroke can be like depression following another major illness that affects a person’s life but does not injure the brain — such as a heart attack or cancer.

You might think that in someone who has difficulty talking or understanding speech, or difficulty moving his arms and legs, depression is the least of his problems. But the mental anguish of depression isn’t a minor concern. Left untreated, depression can undermine efforts at rehabilitation and worsen cognitive disabilities.

That’s what happened at first to my patient, until his depression was successfully treated. Depression after a stroke is associated with poorer outcomes a year after the stroke has occurred. It’s also associated with a higher death rate in subsequent years.

Fortunately, antidepressants seem to be fairly effective. In 2008, scientists published a review of the research in this area. They concluded that the medications had a “small but significant” effect on post-stroke depression.

What’s more, the benefits of antidepressants may not be limited to relieving depression; they may positively affect areas and networks in the brain that improve other impaired functions as well.

Studies published in the last couple of years have found that certain antidepressants (in combination with physical therapy) can help with recovery from stroke-induced paralysis, muscle weakness and overall disability.

If you haven’t already done so, talk to your father’s doctor about his depression. Ask the doctor to recommend a psychiatrist who has experience working with stroke patients, or find out if there is a mental health professional affiliated with your father’s rehab program.

Treatment of stroke has improved greatly in this country. People who would have died or been severely disabled now do quite well. That’s due, in part, to powerful drugs that can quickly open blocked blood vessels in the brain. Perhaps the next major gains in stroke care will come during the recovery period.